Drilling machine



July 8, 1969 B, PQAGE 3,454,114

DRILLING MACHINE Filed June 4, 1968 sheet of 5 A fm2/V515 Juy 8, 1969 L B. POAGE 3,454,114

DRILLING MACHINE Filed June 4, 1968 Sheet of 3 I N VENTOR. iM/V0 5. PA'

July 8, 1969 1 B. POAGE 3,454,114

DRILLING MACHINE Filed June 4, 1968 y sheet v 3 of s f f AE 1N VEN? 0R,

'L DV-pf @Wwf/Md Arroz/@kf United States Patent() U.S. Cl. 173-152 6 Claims ABSTRACT F THE DISCLOSURE A traveling support frame is mounted for up and down travel by two parallel guide columns secured at their lower ends to a base frame. A portion of the traveling frame projects forwardly of the drive columns and supports coaxially related motor, reducting gearing and drive head means which are closely adjacent to and in parallelism with the -two columns. The traveling frame and equipment carried thereby are moved up and down by thrust ram means comprising a downwardly opening, upwardly projecting, piston chamber having a lower mounting portion rigidly secured to the traveling frame and a downwardly directed piston having a lower mounting portion secured to the base frame.

BACKGROUND OF THE INVENTION Field of the invention The present invention relates to earth boring or drilling machines. It particularly relates to mechanism for supporting and ldriving the rotary drilling equipment of such machines.

Description of the prior art The present invention relates to an earth boring or drilling machine which in some respects constitutes an improvement over the earth boring machine disclosed by U.S. Patent No. 3,220,494, issued on Nov. 30, 1965 to Robert E. Cannon et al. The machine shown by this patent is relatively bulky owing to the inclusion in its makeup of four corner positioned support columns and thrust or drive rams having upwardly directed pistons. Such arrangement of the rams makes it necessary to locate the drilling equipment below the traveling cross frame and requires an extra connecting structure between the upper ends of the pistons and the traveling cross frame, for transmitting the forces involved to the guide columns.

Caldwell 2,334,312 and Mistrot 2,956,782 disclose examples of other known types of drilling machines. How ever, these patents are not concerned with mounting rotary drilling equipment on a traveling cross frame, or of driving such a cross frame, in such a manner that the drill head is in use movable between a position near the ground and a retracted position spaced therefrom, with a minimum of load bearing structure being used for conveying the driving forces from the traveling frame to a fixed main frame.

SUMMARY OF TH-E INVENTION This invention primarily relates to constructional details and relative placement of certain key components of a drilling machine, making such machine relatively compact and relatively lightweight, lwithout a substantial sacrifice in capacity.

Drilling machines of the present invention are characterized by rotary drilling equipment mounted on a traveling support f-rame forwardly of a single pair of parallel guide columns on which such traveling frame is mounted for up and down travel. The traveling frame is moved by one or more thrust rams comprising a downwardly Patented July 8, 1969 bICCv opening upwardly projecting piston chamber having a lower mounting portion secured to the main frame of the machine. Owing to this arrangement the traveling frame can be and is made relatively small in size but still constitutes an eicient structural link for transmitting drilling forces to the guide columns.

These and other features, advantages and characteristics of the earth boring equipment of the invention will be apparent from the following detailed description of typical and therefore nonlimitative embodiments of the invention, and from the accompanying illustrations.

BRIEF DESCRIPTION OF THE DRAWING In the drawing like letters and numerals refer to like parts, and:

FIG. 1 is a view in side elevation of the equipment with the drilling rig mounted on the base member in an upright position, with a crawler tractor type transporter thereof shown in phantom, and with the foreground thust ram shown in section;

FIG. 2 is a rear elevational view of the equipment readied for transport, with the transporter shown in phantom;

FIG. 3 is a front elevational view of the drilling rig, showing the `driving means in a lowermost position;

FIG. 4 is a view similar to lFIG. 3, but showing the drive means in a partially raised position, showing a drill stern being stabilized by a bushing at the work table, and showing the drive head cut away to expose the universal joint;

IFIG. 5 is a view partially in axial section and partially in elevation of one of the thrust rams;

lFIG. 6 is an exploded pictorial view of the major components of the equipment;

lFIG. 7 is a side elevational view, -with some parts in section, of the motor, transmission and drive head assembly; and

FIG. 8 is an enlarged scale sectional View of the portion of FIG. 7 showing the drilling fluid delivery collar and the universal joint.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring more specifically to the several figures of the drawing, the mobile drilling machine that is illustrated comprises a transporter 10 and a drilling assembly 12 adapted to be carried by the transporter 10, and to be moved between its transport position on the transporter and drilling position off from the transporter, by equipment carried by the transporter.

As perhaps best shown by FIG. 6, the drilling assembly comprises a lower or main frame 14 having side parts 16, 18 interconnected at the top by a generally U-shaped plate 20 and at the bottom by a work table 22. The upper plate 20 has two side portions 24, 26 and an interconnecting rear portion 28, but is open at the front. Openings 30, 32 are provided in the rear side corners of plate 28 to receive the lower end portions 34, 36 of a pair of guide columns 38, 40. The columns 38, 40 are provided with mounting collars 42, 44 which rest on the upper surface of plate 28 about the openings 30, 32, and are welded or otherwise firmly secured to the plate 28. The upper ends of the columns 38, 40 are shown to each include upwardly projecting keys 46, 48, each of which is adapted to lit within a locking slot 50, 52 for it at the opposite ends of a head frame 54. The head frame 54 is secured to the upper ends of the columns 38, 40, such as lby the use of anchoring bolts on each side of the mated keys and slots 46, 50 and 48, 52. The mated keys and slots 46, 50 and 48, 52 prevent rotation of the head frame 54 relative to the columns 38, 40.

Two motor and lubrication pump units 56 may be positioned on the main frame 14 within or below the lower end portions 34, 36 of the columns 38, 40.

The guide columns 38, 40 function to support and guide a movable cross frame means 58. The cross frame means 58 is formed to include a pair of elongated guide sleeves 60, 62 at the two rear corners of such cross frame means 58 which surroundingly engage the columns 38, 40.

The cylindrical boundaries of the guide sleeves 60, 62 are formed by wall means, an inner portion of which is also a part of the wall of a larger cylindrical sleeve 64 which receives the lower portion of the gear box 66 and perhaps an upper portion of the drive box 68.

A pair of mounting sockets 70, 72 are located laterally outwardly, on the opposite sides, of the sleeve 64 and preferably include an inner wall portion which is also a portion of the wall forming sleeve 64. The sockets 70, 72 are spaced forwardly of the sleeves 60, 62 and are formed about center axes x, y which are preferably in coplanar parallelism with the center axis z of sleeve 64. Preferably, inner portions of the side walls forming the sockets 70, 72 are also portions of the side wall forming sleeve 64. It may be said that the cylindrical sleeves 60, 62 and the cylindrical sockets 70, 72 are circumferentially spaced about and tangentially related to the large sleeve 64. Also, the portions of cross frame means 58 forming the sockets 70, 72 and the sleeve 64 are supported in cantilever fashion out forwardly of the guide sleeves 60, 62 and the guide columns 38, 40 along which they travel.

The cylindrical sockets 70, 72 are preferably longitudinally split into two halves, the inner one Of which is an A integral part of the cross frame means proper. The outside half 74, 76 is removably secured in place, such as by means of bolts 78 (FIG. l). During assembly the lower mounting portions 78, 80 of a pair of hydraulic rams 82, 84 are set into the inner halves of the sockets 70, 72. Then the outer sections 74, 76 are added and bolted in place. The mounting portions 78, 80 are parts of the cylinders or piston chambers 82, 84, and in this manner the cylinders 82, 84 are firmly secured to the traveling cross frame means 58, in a position of parallelism with the guide columns 38, 40. During assembly the lower ends 86, 88 of the piston are inserted downwardly through openings 90, 92 in the upper plate 28 of main frame 14. Eye openings 94, 96 in the lower end pieces are aligned with openings 98, 100 in the side parts 16, 18 of the main frame 14. Cross pins, one of which is shown in FIG. 6 and designated 102, are inserted through the aligned openings 94, 98 and 96, 100 for the purpose 0f securing the lower ends of the pistons to the main frame 14.

Herein the term cylinder is used not to designate shape, but rather to denote the functional components of the hydraulic rams in which the pistons are slidably received. It is to be understood that although the cylinders or chambers 82, 84 are shown to be cylindrical in shape, and this is the preferred shape of these components, they could just as well be made square, rectangular etc. in cross-section.

Hydraulic uid for raising the traveling cross frame means 58 is delivered by a flexible conduit or hose 104 into an inlet port (FIG. at the lower end of the piston. The piston rod 106 includes a central passageway 107 through which the fluid flows up to an upper chamber between the closed upper Wall 108 of the cylinder and the upper surface of a piston head 110. During upward travel of the cylinder and other components any hydraulic fluid within the annular chamber 112 surrounding the piston rod 106 is returned to the uid reservoir via hose 114. As will be evident, a reverse or downward drive of the movable drilling components is effected by reversing the direction of iiow through conduits 104, 114.

Referring now to FIG. 7 in particular, the drilling equipment carried yby the traveling cross frame means 58 comprises a motor 116, speed reduction gearing within gear box 66 and drive head means within drive box 68.

The motor 116, the speed reduction gearing and the drive head means are coaxially arranged on the cross frame means 58, in parallelism and closely adjacent the rigid guide columns 38, 40.

As best shown by FIG. 7, a lower mounting flange 118 on the motor 116 is secured to an upper mounting flange 120 on the drive box 66. The central output shaft 122 of the motor 116 projects downwardly into the upper portion of the drive box 66 and carries a first sun gear 124 at its lower end, The transmission is a two speed transmission. Sun gear 124 always meshes with three large diameter planet gears 126 (one of which is shown in FIG. 7) constituting parts of three dual planet gear elements which are journaled at their ends in portions of the drive box housing 66. Such elements include small diameter planet gears 128 which always mesh with a ring gear 130, coaxially related to the sun gear 124. Ring gear includes internal teeth 131 as well as external teeth 132. The upper end gear 133 of an axially movable gear unit 134 also includes inner and outer teeth 135, 137, respectively when unit 134 is moved into and supported in its upper position its inner teeth 135 mesh with gear 124 and ring gear 130 turns free. This is high7 gear, when unit 134 is moved into and supported in its lower position, the external teeth 137 mesh with internal teeth 131 and gear 130 becomes a part of the drive train. This is low gear.

Ring gear 130 merely oats radially between the three gears 128. Axially it is supported on and by plates 127 which either turn with or are freely mounted about the lower end portion of gear 128. Gear unit 134 is moved axially and is supported by a fork (not shown) which engages unit 134 at 129.

A smaller sun gear 136 at the opposite end of unit 134 meshes with three traveling plant gears 138 (one of which is shown in FIG. 7) which ride about a stationary internal ring or orbit gear 139. The gears 138 are journaled for free rotation about fixed shafts 140 which are carried at the large diameter end of a center shaft 142, coaxially related to shafts 122 and 134. The smaller diameter end of shaft 142 carries a sun gear 144 which meshes with three traveling planet gears 146. Gears 146 travel around a lixed internal ring or orbit gear 148 as they rotate. The gears 146 are mounted for free rotation about xed support shafts 150 which are carried at the larger diameter end of a main or output shaft 152. The main shaft 152 is journaled for rotation at its upper end by a combined bearing 154 and at its lower end by a larger combined bearing 156. As used herein, the term combined bearing means a bearing capable of carrying both radial and axial or thrust loads.

The drive head means includes a member 158 having a tubular upper portion 159 which is insertable upwardly into the lower end of the drive box 66 in concentric surrounding engagement with the lower end of main shaft 152. A transverse internal ange 160 carried by tubular shaft 158 abuts against the lower end of main shaft 152. A plurality of anchoring bolts 162 are used for securing the internal ange 168 to the lower end portion of the main shaft 152. Element 158 also includes a bell like lower portion 164 which has substantially spherical inner and outer surfaces in at least a part of its extent. The drive head means also includes a box type connector 166 having an upper ball portion 168 with an outer spherical surface that mates with the inner spherical surface on bell 164. A mating set of generally axially extending splines 170 extend circumferentially about the ball 168 and the bell 164 and serve to transmit torque from one to the other, while permitting angular movement of the ball 168 within the axial planes of the splines. The drive head means also includes a retainer sleeve 172 which is boltable to the ball portion 168, such as by bolts 174. The upper portion of sleeve 172 includes an inwardly facing spherical surface which contacts and rides on the outer spherical surface of bell 164. Preferably, an annular dirt seal 176 is carried at the upper end of element 172, andy is constructed to be resilient enough to give during angular movement between the upper and lower parts.

The upper ball end portion 168 of the box 166, the bell portion 164 of tubular shaft 158 and the retainer sleeve 174 together form a universal joint for connecting the drive head to the main or output shaft 152. Such joint functions to isolate the shaft 152, its support bearings 154, 156 and the remainder of the speed reduction gearing.,f rom moments caused by bending or other stressing of the drill stem DS connected to the drive head.

As best shown by FIG. 8, the head box 166 is preferably mounted for a limited amount of axial travel relative to its carrier 167 by means of a set of mated splines 178. A lubricant passageway 180, 182 may be provided for delivering a suitable lubricant to the spherical surfaces 165, 169.

A stationary drilling fluid delivery collar 184 is secured to the lower endy of the drive box 66 in concentric surrounding engagement with the rotating, generally cylindrical portion 159 of a tubular element 158. A rotary sleeve 185 immediately vsurrounds the cylindrical portion 159 of element 158, and the collar 184 surrounds the sleeve 185. Collar 184 includes an upper flange 188 by which it is bolted or otherwise secured to the lower end of the drive box housing 66. A suitable sealing ring 190 is located in a Well formed in the upper end of collar 186. Additional seals 192 are provided both above and below an annular manifold chamber or passageway 194. One or more drilling fluid inlets 196 are provided for delivering the drilling fluid into manifold 194. Delivery ports 198 extend through sleeve 184 and are in communication with the manifold 194, and also with the hollow interior 200 of the drive head via radial passageways 202. A sealing plug 204 is secured to the mounting flange 160 and closes the central opening inwardly of the flange 160, so as to prevent movement of the drilling fluid upwardly. A tubular nozzle 207 is bolted to the underside of flange 160 and serves to direct the fluid into box 168 and away from the machined mating spherical surfaces 165, 169.

Lubricant fittings 208 are provided for delivering lubricant to the regions of the seals 190, 192. Collar 186 is itself a bearing and bearing surfaces exist where it makes contact with the bearing sleeve 184.

The annular drilling fluid supply collar 186 is employed because the motor 116 and the speed reduction gearing are located above the upper end of the drill stem. However, it is contemplated that a hollow drive shaft 122 may be used in the motor 116 so that a drilling fluid delivery tube can be inserted through the motor 116 and the reduction gearing down to the upper end of the drill stem DS, enabling the use of a top positioned swivel such as s wivel 176 shown by Cannon et al. U.S.y

Patent No. 3,220,494.

As clearly shown by FIGS. 3 and 4, for example, the coaxial motor and speed reduction gearing means are in effect contained in a single elongated tubular housing (of composite form), and said housing is partially nested in the space between the parallel guide columns 38, 40. The inner surface of the head frame 54 is of concave curvature laterally, so as to also accommodate a peripheral portion of such housing.

In use the above described drilling equipment is mounted onto a rigid base means which is preferably pinned, bolted, or otherwise firmly secured to the supporting material at the drill site. If the material is rock, the main frame 14 may be directly connected to it. Or, it may be necessary to rigidly enplace a base member in fixed position on the floor or supporting surface at the drill site. The base member may be of concrete, a metallic member or a combination of both. In the illustrated embodiment the base member is formed by pouring a concrete pad on the floor about the drilling point. A metallic base means is positioned on the concrete, is secured to the floor, and with the concrete forms the base member. In other installation the concrete may be dispensed with, or the metallic base members may be dispensed with.

Referring again to FIG. 6, the metallic base means 210 is shown as comprising a pair of side parts 212 and an interconnecting frame 214. The base assemby 212, 214 is in effect a flat-bottomed base member rigidly anchorable to the floor in substantially surrounding relation to vthe axis of the hole to be formed. As used herein, the expression substantially surrounding means that the base member has supporting parts (212) on at least oppositesides of the drill hole and also endwise of a transverse line cutting across the side members 212 and coinciding with the axis of the drill hole.

Each base member 212 comprises a flat bottom plate 216 and apair of laterally spaced upright walls or plates 218. Portions of the flat bottom plate 216 project laterally outwardly, from the outer wall 218 to form a flange through which mounting pins or bolts may be inserted. The interconnecting frame may comprise laterally spaced side members 220 interconnected by box like end members 222. The side members 220 are bolted or otherwise firmly secured to the inner side walls 218 of the base members 212.

The drilling equipment commencing with main frame member 14 on up is preferably adjustably axable in position on the base member. In the preferred embodiment this lis achieved by providing a pivot pin opening 224 at the lower rear corners of the main frame side parts 16, 18, generally vertically below the rear side boundary of the guide columns 38, 40. The side members 16, 18, which are each formed by a pair of spaced, Vertical parallel plates 226, 228, are narrower than the spacing between the upright plates 218 of the base members 212. The lower portions of the side members 16, 18 are normally nested between the side plates 218 of members 212, with the openings 224 aligned with openings 230, 232 in the plates 218. Husky pivot pins 234 serve to pivotally mount the two rear corners of main frame 14 to the respective rear ends of the base members 212.

The forward end of the main frame 14 is angularly adjustable with respect to the base means 210 by means of a pair of threaded turnbuckle assemblies 236, 238, each of which is adjustable between respective lower sleeves 240, 242 and respective upper sleeves 244, 246. The lower sleeves 240, 244 are pivotally mounted by fixed pins 250 which extend through aligned openings in the forward end portions of the side plates 218, and through the sleeves 240, 242 between such openings. The upper sleeves 246, 248 are pinned by respective pins 254 to an aligned pair of the respective series of adjustment holes 256, 258 arranged vertically along the forward edges of the respective plates 226, 228.

As will be evident, angular adjustment of the drill line DL with respect to the plane of the bottom of the base means 210 occurs about the pivot axis provided by the pins 234. Coarse adjustment is affected by selective placement of pins 254 in the desired pairs of adjustment openings 256, 258. Fine angular adjustment is affected by varying the length of the turnbuckle assemblies 238, 240'.

In the preferred embodiment the transporter 10 is of a crawler tractor type. It includes a central supporting frame 260 and a pair of side located power driven tracks 262, 264.

As best shown by FIGS. 1 and 6, a pair of vertical lever plates 266 are secured to the rear portion of the main frame 14 laterally inwardly of the opposite sides thereof. A pair of rams 268 are interconnected between rear portions of the transporter frame 260 and the upper ends of the lever plates 266. A pair of loa-ding links 270 are interconnected between the pivot pins 234 on the base members 212 and pivot pins mounted near the forward corners of the transporter frame 260. Links 270 are pivotal at each of their ends, and the piston-cylinder assemblies 268 are pivotal at each of their ends. Bearing point notches 272 are provided in upper rear portions of the vertical plates 266. The spacing between the pivotal axes of pins 234 and the center of the notches 272 is substantially equal to the length of the links 270 between the two pivot axes provided at the opposite ends thereof.

Referring now to FIG. l, when it is desired to move the drilling equipment from a generally upright use position into a supine transport position (FIG. 2), the pistons of units 268 are retracted back into the cylinders of such units 268, causing the entire equipment to pivot rearwardly about the axes of pins 234. The equipment from main frame 14 on up is disconnected from the base means 210, and the piston-cylinder units 268 are actuated t tilt the equipment clear back until the notches 272 engage the transverse support bar 274, or the like, mounted at the forward end of transporter frame 260 between the rear pivot axes of the links 270. Further retraction of the pistons causes the equipment to pivot about support pin 274 down into the supine position depicted by FIG. 2.

A sled type transporter may be used in place of a self-propelled tractor crawler. Other forms of transporter may include a transporter having flanged wheels for engaging rails, or ground engaging wheels, i.e. like a wagon. Or, the machine 12 may be merely carried to the work site by any suitable means either in one piece or in secions, to be assembled at the work site.

The electrical equipment cabinet EC, the operators control panel CP, and the hydraulic power package HPP are transported separately from the drilling equipment.

It is to be understood that the construction of the various key components of the drilling equipment can vary from that illustrated and still remain within the scope of this invention. For example, the two thrust rams 82, 84 may be replaced by a single thrust ram that is centrally positioned with respect to the two guide columns 38, 40. Actually, several combinations as to number and relative placement of the thrust rams and guide columns could be made within the scope of the invention. For example, three columns and three rams could be alternately placed in a circular pattern. Further, although the coaxial arrangement of the drive motor, the gearing and the drive head is preferred, in some installations it may be desirable to employ a different arrangement of these components in which all rotational axes are not coaxial, while still employing the chamber-up thrust ram arrangement characteristic of this invention. The guide columns can be made in a varying number of shapes and from varying types of structural materials. For example, I-beams, wide flange beams, hollow box beams, etc. could be used in place of the cylindrical tubing. The main frame, i.e. the 4ground supported frame, may be varied in a number of ways and may be anchored to the ground in a number of `diiering ways.

F rom the foregoing, various further modications, cornponent arrangements and modes of utilization of the drilling mechanism of the invention will be apparent t0 those skilled in the art to which the invention is addressed within the scope of the following claims.

What is claimed is: I

1. In a drilling mechanism comprising a traveling support frame means, rotary drilling equipment carried by said support frame means, a main frame, and thrust ram means interconnected |between said traveling support frame means and the main frame, wherein said rotary drilling equipment includes a rotary drill head connectable to drill pipe, motor means, and transmission means drivenly connected between said motor means and said drill head, the improvement of:

said thrust ram means comprising an upwardly directed hollow piston chamber having a normally closed upper end and a lower end mounting portion, and a downwardly directed piston slidably receivable in said chamber and having a lower end mounting portion and an upper head portion;

means rigidly afixing the lower end mounting portion of said chamber to said traveling frame means, with the remainder of said chamber extending upwardly above said traveling frame means; means afixing the lower end of the piston to said fixed main frame means;

selectively usable means for simultaneously delivering :a motive fluid between the closed upper end of the chamber and the head portion of the piston, and venting the zone below the piston head, for moving the traveling support frame means and the chamber and rotary drilling equipment mounted thereon upwardly, as an assembly; and

selectively usable means for simultaneously delivering motive fluid to the zone below the piston and venting the space above the piston head, so as to cause a downward movement of the chamber, the traveling support frame means and the rotary drilling equipment, as an assembly.

2. The drilling mechanism of claim 1, wherein the traveling support frame means includes a vertically oriented and elongated socket of split form, having a removable outer portion which includes a clamping wall and mounting flanges outwardly of said clamping wall, land the lower mounting portion of the chamber is snugly received in said mounting socket and is held in place, partially at least by the said clamping wall.

3. The drilling mechanism of claim 1, further comprising a plurality of spaced apart, parallel, rigid support and guide columns having mounting end portions rigidly secured to said iifain frame, and upstanding guide portions, and wherein sidytraveling support frame includes means mounting it for travel along said upstanding guide portions.

4. The drilling mechanism of claim 1, further comprising two spaced apart, parallel, rigid, upstanding support and guide columns having mounting end portions rigidly secured to said main frame, and wherein said traveling support frame includes a rst portion mounted for travel along said upstanding guide columns, and a second portion projecting outwardly from the general plane of said columns in cantilever fashion, with said second portion mounting said rotary drilling equipment.

5. In a drilling mechanism comprising a drilling assembly including a rigid lower frame, parallel column mans rigidly connected to said lower frame, rigid cross frame means mounted for up and down travel along said column means, and drilling equipment carried by said cross frame means comprising a rotary drill head connectable to drill pipe, motor means, and transmission means drivenly connected between said motor means and said drill head, the improvement of? said column means comprising a single pair of spaced apart, parallel columns, and

said cross frame means including a pair of guides which engage the two guide columns, and a substantially larger mounting socket for the said drilling equipment, with said guides `being substantially tangentially joined to said mounting socket, and supporting the said mounting socket, and all of said drilling equipment, in cantilever fashion to one side of the general plane of the two guide columns.

6. The drilling mechanism of cla-im 5, further comprising at least one thrust ram comprising an upwardly directed, downwardly opening, hollow piston chamber having a normally closed upper end and a lower end mounting portion, and a downwardly directed piston slidably receivable in said chamber, having a lower end mounting portion and an upper head portion;

means rigidly aixing the lower end mounting portion of said chamber to said traveling cross frame means, with the remainder of said chamber extending upwardly above said traveling frame means;

means aflixing the lower end of the piston to said lower frame means;

selectively usable means for simultaneously delivering a motive fluid between the closed upper end of the chamber and the head portion of the piston and venting the zone below the piston head;

to move the traveling cross frame means .and the rotary drilling equipment and chamber mounted thereon upwardly as an assembly; and

selectively usable means for simultaneously delivering motive fluid to the zone below the piston and venting the space above the piston head, so as to cause a downward movement of such assembly comprising the traveling cross frame means and the piston cham- |ber and drilling equipment carried thereby.

10 References Cited UNITED STATES PATENTS 2,715,954 8/1955 Rowan -92--117 X 2,807,441 9/ 1957 Sewell 173--159 X 5 2,811,335 10/1957 Fletcher et al 173-23 2,880,707 4/ 1959 McCarthy 91--196 X FOREIGN PATENTS 734,291 5/ 1966 Canada.

10 ERNEST R. PURSER, Primary Examiner.

U.s. C1. XR. 

